THE DISEASE

Typhoid fever is an infectious disease caused by a bacterium called Salmonella typhi. The source of this infectious agent are human carriers i.e. persons who excrete the bacteria through their faeces without having any symptoms. However, for them the typhoid bacteria still live inside their gall-bladders and are excreted a little bit at a time through their faeces. People get typhoid fever if they consume food or water indirectly contaminated with typhoid bacteria from carriers.

The incubation period of typhoid is about 10 - 14 days. During this period, the typhoid bacteria multiply inside the host cells.They are then released into the blood stream resulting in bacteremia and dissemination to various organs of the body. Clinical presentations vary tremendously among patients and range from mild such as headache, diarrhoea, low grade fever and malaise to severe symptoms including splenomegaly, hepatomegaly, delirium and shock. Since symptoms seen with typhoid are similar to other diseases with fever common in areas endemic for typhoid, a definitive clinical diagnosis of the disease is difficult, hence the need for a good laboratory test.

Typhoid fever is endemic in the Asia Pacific region, the Indian subcontinent, Central Asia, Africa and South America. There are no accurate figures on the incidence of typhoid fever. However, WHO has estimated that there are 16.6 million cases of typhoid annually with about 600,000 deaths.

Procedures...